Diabetes mellitus is a highly significant health problem, affecting approximately 16 million people in the United States alone. Our understanding of the pathogenesis of diabetes has benefited immensely from the molecular genetic analysis of the disease both in human and in rodent models. Recent breakthroughs in microarray technology have enabled investigators in the fields of diabetes and endocrinology to simultaneously analyze the expression levels of thousands of genes, the only limitation being the high cost of the commercial microarrays. We propose to establish a new Functional Genomics Core that will provide center investigators with timely and cost-effective expression profiling. The core will be an extension of the facility established through the NIDDK funded project on "Functional Genomics of the Developing Endocrine Pancreas" (R24-DK56947 to Dr. Kaestner), which has pioneered microarray analysis in the Diabetes Center. The newly established Core will utilize equipment, clone sets and experience generated through this R24 grant. The core will offer the following services: a) provide both 70mer oligo and PCR product microarrays for gene expression analysis using mouse and human samples b) hybridization of both Affymetrix and Core arrays c) analysis of microarray data and training of Center investigators in expression profiling d) printing, hybridization and analysis of custom microarrays for Center investigators. The Functional genomics Core will also annotate and store the expression data in our web-accessible database where desired by Center investigators. The Core will interact closely with the other DERC cores, in particular the Mouse Phenotyping, Physiology and Metabolism Core (Rex Ahima). Correlation of the phenotypic analysis performed on genetically altered or metabolically challenged mice with their expression profile will greatly enhance the power of each individual analysis.